Representatives of the world's two biggest economies -- and two biggest polluters -- have sat down to address climate change. On Wednesday, US Special Presidential Envoy for Climate John Kerry wrapped up three days of discussions in Beijing with Chinese leaders.

Kerry said he went to China to "unstick what has been stuck."

Chinese delegates had been unwilling to talk since former US House Speaker Nancy Pelosi visited Taiwan last August. However, they have reopened the door to working together. Kerry said he wanted to "break new ground" but added that reaching a consensus will need a "little more work."

Kerry told Vice President Han Zheng that the climate crisis is a "universal threat" and should be treated as a "freestanding" challenge. Han said cooperation is predicated on "mutual respect."

The two agreed to work "intensively" ahead of the United Nations climate conference, COP28, which starts in November.

Kerry said they will meet again over the next few weeks on phasing out coal, reducing methane emissions, and integrating renewable energy.